Double-throw snap-switch



(No Model.)

E. M. HEWLETT. DOUBLE THROW SNAPSWITGH.

No. 524,384. l Patented Aug. 14, 1894.

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NTTED STATES PATENT '@EETQE.

EDWARD M. HEWLETT, OE sCHENECTADY, NEW YORK, AssICNOR TO THE GENERAL ELECTRIC COMPANY, OE NEW YORK.

DOUBLE-TH ROW SNAP-SWITCH.`

SPECIEIGATION forming part of Letters Patent No. 524,384,01ated August 14, 1894.

Application filed July 2, 1894.. Serial No. 516,259. (No model.) l

To all whom it may concern:

Be it known that I, EDWARD M. HEWLETT, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Double-Throw Snap- Switches, of which the following is a specifi-l cation.

ticularly to so-called double-throw switches;

My invention relates to switches for break- 1 g circuits carrying heavy currents, and parthus be ruptured at two pointsat thel same time; by which arrangement I avoid the destructive arcing which Often accompanies the opening of such a switch. I also provide means for holding the switch open in a central position so that when the operator desires to open it from either direction, he has only to give it a positive thro-w, and it will at once assume this central position without estab lishing a circuit upon the other side. Many attempts have been made to attain all of these objects in one switch, but so far as I know there are objections to the devices employed.

To accomplish the ends pointed out, I constructmy improved switch of three copper blades hinged together at one end and with a spring extending between., the two outer blades, a handle being attached to the middle blade. The middle or inner blade is rigid with a central piece to which the outer blades are hinged, the inner ends of the hinged outer blades being cut away so that theinner blade may be rotated about its `center to a certain angle before it will engage with the cut away ends of the outer blades to thro'w them from the contacts. This permits me to get the spring' under such tension that when the friction between-the contacts of the Outer blades is overcome by means of the positive contact of the inner blade with the cut away portion of the outer blade, the spring will withdraw the outer blade instantly, thus, as

already pointed out, breaking the circuit at both contacts at the same time.

` In the accompanying drawings I show an embodiment of my invention, Figurel being a plan and Fig. 2 a side elevation of a switch constructed according thereto.

A is a base of eboniteor slate Or other material having suitable vinsulating and refractory properties. It is, in the case illustrated, shown as attached to the base A of wood.

C, C, dac., are the contacts for the knifeblade portion of the switch, C', C being the terminals for the circuits.

E is the handle attached, as already pointed out, to the inner member of the blade of the switch.

Referring now to Fig. 2, the-side elevation shows the inner member Gand the two outer plates F, H, of the switch hinged to a central piece P at k, k, the central blade being riveted t0 the piece Prigidly. Aspring I is suitably attached to the two out-er blades and, as illustrated in Fig. 1, is duplicated upon each side, although a single spring might be employed if desired. The outer blades are shown slightly cutaway on their inner ends at K, K.

The centerpiece P is formed with three cam surfaces M, M, M, and a strong spring supporting a friction roller N, engages at all times with one or the other of these cam surfaces, the upper and lower ones being adapted to hold the switch firmly in engagement with the contacts, while the middle one holds it in an upright position between the two. At L is shown a` central pivot upon which the whole switch swings.'

The operation of the device is as follows: When it isvdesired to break the circuit, the handle E is thrown, describing an arc of about forty degrees, the piece P at the same time compressing the spring by depressing the friction roller N, the handle E forcing up the central blade G and the upper blade F, while the blade H remains in the contacts C, C, thus putting under tension the spring At the same time the blade H is slightly moved forward and its inner end raised by the action of the pivot 7c asit-swings around the pivot L as its center. When the handle has reached the position thus described, the

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inner end of the blade G comes in contact with the cut away portion K of the other blade H, and draws it up from the spring contacts C; when the resistance of these contacts is sufficiently overcome by the motion upward of the blade H, the spring I suddenly snaps away the blade. By this time the handle E will have passed to such a position that the point M upon the cam surface P will have passed the friction roller N, which then engages with the middle cam surface M and holds the switch in its upright position. The operation is the same when the switch is withdrawn from the other contacts.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

l. A double-throw snap-action knife-blade switch comprising a central blade G and spring-actuated outer blades F, H, pivoted to the first blade and having cut-away portions permitting a lost motion of the first blade.

2. A double-throw jack-knife switch, comprising a central blade, two outer blades, and a spring connected from one of such outer blades to the other, the outer blades having cut-away portions pivoted to the central blade and adapted to make positive contact therewith after a definite arc of movement.

3. A double-throw spring-actuated knifeblade switch, comprising,r contacts C, C, a central blade as G, outer blades H and l pivoted to such central blade and having a cut-away portion K adapted to make positive contact with the inner blade after a definite arc of motion, and a cam and friction roller, as P, N, adapted to engage the switch in all ot' its three positions, substantially as described herein.

In witness whereof I have hereunto set my hand this 30th day 0f June, 1894:.

EDWARD M. HEWLETT.

Witnesses:

B. B. HULL, A. F. MACDONALD. 

